Volumetric Analysis Calculations

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Volumetric Analysis Calculations
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Example One

• Jo has a solution of Hydrochloric acid (HCl)
  that she does not know the concentration of. She
  decides to use a standard solution of Sodium
  hydroxide (NaOH), 0.112molL-1, for the titration
• She uses a 15mL pipette to measure aliquots of
  NaOH into her flasks. She then titrates these
  with the HCl from the burette until the indicator
  turns from purple to colourless
• These are her results
• Titres of HCl 23.3mL, 22.8mL, 22.9mL, 22.7mL

• Balanced equation
• ?
• NaOH
• c
• n
• v
• HCl
• c
• n
• v

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Example Two

• Jim has a solution of Sodium carbonate (Na2CO3),
  but the label is missing. To work out the
  concentration he decides to use a standard
  solution of Hydrochloric acid (HCl) with a
  concentration of 0.322molL-1.
• He uses a 20mL pipette to measure aliquots of HCl
  into his flasks. He then titrates these with the
  Na2CO3 from the burette until the indicator turns
  from colourless to purple
• These are his results
• Titres of Na2CO3 18.2mL, 18.2mL, 17.9mL, 18.3mL

• Balanced equation
• ?
• HCl
• c
• n
• v
• Na2CO3
• c
• n
• v

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Example Three

• Jill has a bottle of vinegar (ethanoic acid
  solution CH3COOH). The label says that it
  should have 3.1gL-1 of ethanoic acid in it. To
  work out the real concentration she decides to
  use a standard solution of Sodium hydroxide
  (NaOH) with a concentration of 1.22 x 10-2
  molL-1.
• She uses a 25mL pipette to measure aliquots of
  vinegar into her flasks. She then titrates these
  with the NaOH from the burette until the
  indicator turns from colourless to purple
• These are her results
• Titres of NaOH 22.1mL, 22.5mL, 22.6mL, 22.4mL

• Balanced equation
• ?
• NaOH
• c
• n
• v
• CH3COOH
• c molL-1
• gL-1
• n
• v